Business Description and Organization - Schedule of Ownership Interest, Including Limited Partners (Details)	9 Months Ended
	Sep. 30, 2024
AB
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in company (percent)	100.00%
EQH and its subsidiaries
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in company (percent)	60.00%
AB Holding
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in company (percent)	39.30%
Unaffiliated holders
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in company (percent)	0.70%